Method of curing glue stock



present in green bones.

Patented Nov. 3, 1942 1 2,300,740 METHOD CFCURING GLUE s'rooK Edward Christopher, Chicago, Ill., assignor to Industrial Patents Corporation, Chicago, 111., a

corporation of Delaware No Drawing. -Application December 9, 1938,. Serial No. 244,775

11 Claims. (erase-1 18) This invention relates to a method of curing gelatinous material stock, particularly bones.

One of the objects of this invention is to provide a method of treating bones to yield high test gelatinous material.

Another object of this invention is to provide a method of cleaning bones preparatory to the extraction of gelatinous material therefrom.

Further objects and advantages will become apparent from the description and claims which follow. I

Thepresent invention contemplates the treatment of green bones with a small amount of a water soluble salt of a metal whose oxide or hydroxide is soluble in excess alkali and whose salts are not precipitants for gelatinous material.

The term gelatinous material is used herein and it is to be understood to designate all grades of animal gelatin and glue including those inr termediate products commonly known as low grade gelatin and high grade glue.

In the conventional practice of extracting gelatinous material, for example, glue, from bones, the green or fresh bones are crushed and washed with cold water to remove foreign matter such as blood and dirt from the surface. After draining, the crushed bones are cooked under steam pressure. I have discovered that if the green or fresh bones are first treated with a small amount of a water soluble salt of a metal whose oxide or hydroxide is soluble in excess alkali, the final gelatin or glue product is a much higher grade material. This treatment of green bones results in a coagulation of the blood and certain albuminous materials and permits these materials to be easily washed away to produce a clean type of bone. The treatment of bones with the salt and subsequent washing effects a removal of adulterants or diluents. These inert substances, such as blood and certain albuminous materials, dilute the glue or gelatin and thereby lower the jelly strength and viscosity.

Water soluble salts of aluminum, copper, tin, and zinc may be employed in cleaning green bones. Suitable zinc salts are zinc sulphate, zinc chloride, or zinc nitrate. Zinc salts are desirable because they possess certain properties which destroy destructive enzymes which are Zinc sulphate is a convenient zinc salt since it is inexpensive and has the desirable enzyme destroying properties. Aluminum salts for the most part are too costly but are entirely satisfactory for my invention. Copper falls within the class of metals whose salts are soluble in excess alkali for the purpose of my invention since its salts are soluble in ammonium hydroxide. Copper salts are also satisfactory for the treatment of green bones; however, they are undesirable if a light colored glue is to be. produced. The copper salts apparently react with certain of the proteins and thereby discolor and darken the glue. Sodium zincate, sodium stannate, and sodium aluminate are also satisfactory for cleaning bones.

vIn the extraction of gelatinous material, such as glue, from fresh bones, according to my method, the bones are crushed and placed in a cooking vessel. 'A' small amount of the desired metallic salt is added together with a sumcient amount of water to cover the bones. I have found that. the addition of about 0.5 per cent zinc sulphate, sodium aluminate, sodium stannate or sodium zincate, based upon the weight of the bones, is very satisfactory. The bones and salt solution are then heated to about 1'70 degrees F. to degrees F. for one hour. I have foundthat it is advantageous to agitate the salt solution during the cooking period. The introduction of compressed air at the bottom of the cooking tank during the heating period serves as a suitable means for agitating the solution; however, any method of agitating the solution may be employed. The saltsolution is then allowed todrain, and the bones rinsed or washed with warm water to remove the salt and any material which may have beenreleased during the heating period. V i

The bones are then cooked under steam ressure in the conventional manner, afterv hich they; are covered with hot water to extra gelatinous material. The extract cont ining gelatinous material is drained and the cooking process repeated at increasing pressures at each cook until all of the glue or gelatin has been extracted from the bones. The extract is concentrated, chilled, and dried in any conventional manner.

The properties of glue and gelatin prepared from reen bones treated with a water soluble salt of a metal whose oxide or hydroxide is soluble in excess alkali are superior to the properties of glue and gelatin prepared by conventional methods. Glue, for example, made from bones treated with the salt has a higher jelly test and viscosity than glue made in the conventional manner, as is apparent from the following data:

Average test of glue made from green bone by treatment with zinc sulphate 'the The temperature and time at which the green bones are treated with the salt solution are not critical and may be varied as desired, the specific temperature and time set forth above having been found to be convenient. It is apparent that if lower temperatures are employed, the time of treatment will necessarily be greater. If higher temperatures are employed, the time of treatment may be reduced. However, it is not feasible to increase the temperature too much since high temperatures adversely alTect the properties of the glue and gelatin.

I claim:

1. The method of preparing gelatinous material from bones which comprises heating the bones in a dilute aqueous solution containing a substance of the class consisting of water soluble salts of metals whose oxides are soluble in excess alkali and water soluble salts of metals whose hydroxides are soluble in excess alkali, separating the salt solution from the bones, washing the bones, and extracting the gelatinous material from the bones.

2. The method of preparing gelatinous material from bones which comprises heating the bones in a dilute solution of a zinc salt, separating the salt solution from the bones, washing the bones, and extracting the gelatinous material from the bones.

3. The method of preparing gelatinous material from bones which comprises heating the bones in a dilute solution of zinc sulphate, separating the salt solution from the bones, washing the bones, and extracting the gelatinous material from the bones.

4. The method of preparing gelatinous material from bones which comprises heating the bones in a solution containing 0.5 per cent zinc sulphate, based upon the weight of the bones, at a temperature between 1'70 degrees F. and 180 degrees'F. for fifteen to sixty minutes, separating the salt solution from the bones, washing the bones, and extracting gelatinous material from the bones.

5. The method of preparing gelatinous material from bones which comprises heating the bones in a dilute solution of sodium zincate, separating the salt solution from the bones, washing the bones, and extracting thegelatinous material from the bones.

6. The method of preparing gelatinous material from bones which comprises heating the bones in a dilute solution of sodium aluminate, separating the salt solution from the bones, washing the bones, and extracting the gelatinous material from the bones.

7. In the preparation of gelatinous material from bones, the treatment of the bones with a dilute solution of a zinc salt at a sufficiently high temperature and for a sufficient period of time to permit blood and albuminous material to be washed from the bones before extraction of the gelatinous material.

8. In the preparation of gelatinous material from bones, the treatment of the bones with a dilute solution of zinc sulphate at a sufficiently high temperature and for a suflicient period of time to permit blood and albuminous material to be washed from the bones before extraction of the gelatinous material.

9. In the preparation of gelatinous material from bones, the treatment of the bones with a solution containing 0.5 per cent zinc sulphate, based upon the weight of the bones at a sufiiciently high temperature and for a suificient period of time to permit blood and albuminous material to be washed from the bones before extraction of the gelatinous material.

10. In the preparation of gelatinous material from bones, the treatment of the bones with a dilute solution of sodium zincate at a sufiiciently high temperature and for a sufficient period of time'to permit blood and. albuminous material to be washed from the bones before extraction of the gelatinous material.

11. In the preparation of gelatinous material from bones, the treatment of the bones with a dilute solution of sodium aluminate at a sufliciently high temperature and for a sufficient period of time to permit blood and albuminous material to be washed from the bones before extraction of the gelatinous material.

EDWARD F. CHRISTOPHER. 

